LITTLE ROCK  Much of the northern half of Arkansas is set to be under a winter storm watch beginning Wednesday night for a system that could lead to significant ice accumulations, forecasters said.

The weather service said in a statement that the northern half of the state could see a quarter-inch to a half-inch of ice with light accumulation starting Wednesday and increasing into the night and the next day. It said a "significant ice storm" may develop.

"Roads may become treacherous," the agency said in a statement. "Especially bridges and overpasses. Widespread power outages are possible."

The watch area includes more than 20 counties roughly north of a line from Fort Smith to Russellville to Conway to Searcy. Northeast Arkansas as well as Little Rock are not included in the watch.

John Robinson, warning coordination meteorologist for the National Weather Service in North Little Rock, said the sleet and freezing rain would begin during the day Wednesday in western Arkansas before moving east in two rounds.

"For those wondering if some of this is going to reach Ice Storm proportions, yes, that could very well occur, especially in northwest and north central sections and in the Ouachita Mountain region," Robinson said in an e-mail. "... I outlined the northern half of the state for the winter weather. There is a reasonable possibility that some ice could work somewhat farther south than that, so keep up with later forecasts."